Computing systems today are becoming more and more complex. In the past, computing systems may have included productivity applications such as a word processor and a spreadsheet program whose functions were simply to create text documents and compute numbers. Today those same productivity applications include complex features, such as embedded programming environments. In other words, productivity applications today may include the ability to embed executable code within the documents themselves. This embedded code enables the features of the productivity application to be programmatically manipulated.
Many sophisticated users employ software developers to write or develop custom software programs (e.g., ‘macros’) within these embedded programming environments. For example, a company may employ developers to write customized software that executes in conjunction with a productivity application, such as a word processor, that is used enterprise-wide. The customized software may include functionality to assist the users with their ordinary tasks or to automate some of those tasks.
Such customized software creates an opportunity for malicious code or viruses to be introduced into a user's document. For example an outsider could receive an e-mail with a document having embedded code that is malicious. For these reasons, safe-software practices need to be applied to this embedded code. For example, code-signing is a common method of ensuring that a software program has not been modified since it was signed. Many companies take advantage of code signing for any customized software that they develop. Commonly, productivity software that allows customized embedded code to be developed includes the ability to sign their embedded code.
As applications develop and new versions are released, new features and capabilities are often included. Unfortunately, this creates a dilemma with signed embedded code in documents that are shared between users of different versions of the same application. Older versions of an application are unable to verify a signature for features that exist only in newer versions of the application. An adequate solution to this dilemma has eluded those skilled in the art, until now.